public double distance(double n1, double e1, double n2, double e2)       {           double jl_jd = 102834.74258026089786013677476285//每经度单位米;           double jl_wd = 111712.69150641055729984301412873//每纬度单位米;           double b = Math.abs((e1 - e2) * jl_jd);           double a = Math.abs((n1 - n2) * jl_wd);           return Math.sqrt((a * a + b * b));         }

这里用的是百度地图的经纬度，参数是百度地图上获取的2个点的经纬度